: An object of type To.
Each bit of the value representation of the result
is equal to the corresponding bit in the object representation
Padding bits of the result are unspecified.
For the result and each object created within it,
if there is no value of the object's type corresponding to the
value representation produced, the behavior is undefined.
If there are multiple such values, which value is produced is unspecified.
A bit in the value representation of the result is indeterminate if
it does not correspond to a bit in the value representation of from
corresponds to a bit of an object that is not within its lifetime or
has an indeterminate value ([basic.indet]
For each bit in the value representation of the result that is indeterminate,
the smallest object containing that bit has an indeterminate value;
the behavior is undefined unless that object is
of unsigned ordinary character type or std::byte
The result does not otherwise contain any indeterminate values.